dotnet/runtime · error · RuntimeError

Pass only one tiering option.

Error message

Pass only one tiering option.

What it means

Raised by superpmi_benchmarks.py main() at src/coreclr/scripts/superpmi_benchmarks.py:423 when both --tiered_compilation and --tiered_pgo are passed. The two are mutually exclusive: --tiered_pgo already implies tiered compilation (it sets both DOTNET_TieredCompilation=1 and DOTNET_TieredPGO=1), and a benchmark collection must isolate a single tiering configuration.

Solutions

1. Pass exactly one of --tiered_compilation or --tiered_pgo (or neither for the default).
2. If you want PGO, use only --tiered_pgo.
3. If you want tiered compilation without PGO, use only --tiered_compilation.

Example fix

// before
python superpmi_benchmarks.py ... --tiered_compilation --tiered_pgo
// after
python superpmi_benchmarks.py ... --tiered_pgo

if args.tiered_compilation and args.tiered_pgo:
    parser.error('Pass only one tiering option: --tiered_compilation or --tiered_pgo, not both.')

When it happens

Trigger: Invoking superpmi_benchmarks.py with both --tiered_compilation and --tiered_pgo on the same command line.

Common situations: Copy-pasting flags from two different pipeline jobs; assuming more flags = broader coverage.

Related errors

• Cannot find System.Private.CoreLib.dll at
• Collection 'smoke_tests' is only available for 'nativeaot'…
• {coreclr_args.mode}
• Could not determine JIT-EE version
• Invalid arch.

AI-assisted analysis of dotnet/runtime@60108ba66e (2026-08-10). Data as JSON: /api/errors/c78c703963756b6f. Report an issue: GitHub.

Appendix: source

Thrown at src/coreclr/scripts/superpmi_benchmarks.py:423

        print(f"-strip failed. Copying {old_mch_filename} to {new_mch_filename}.")
        copyfile(old_mch_filename, new_mch_filename)
        copyfile(old_mch_filename + ".mct", new_mch_filename + ".mct")
        return

    # Create toc file
    run_command([mcs_exe, "-toc", new_mch_filename])


def main(main_args):
    """ Main entry point

    Args:
        main_args ([type]): Arguments to the script
    """
    coreclr_args = setup_args(main_args)

    if coreclr_args.tiered_compilation and coreclr_args.tiered_pgo:
        raise RuntimeError("Pass only one tiering option.")

    all_output_mch_name = os.path.join(coreclr_args.output_mch_path + "_all.mch")
    build_and_run(coreclr_args, all_output_mch_name)
    if os.path.isfile(all_output_mch_name):
        pass
    else:
        print("No mch file generated.")

    strip_unrelated_mc(coreclr_args, all_output_mch_name, coreclr_args.output_mch_path)


if __name__ == "__main__":
    args = parser.parse_args()
    sys.exit(main(args))

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